NOAO > Observing Info > Approved Programs > 2013A-0419
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NOAO > Observing Info > Approved Programs > 2013A-0419 |
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PI: Chris Fassnacht, UC Davis, cdfassnacht@ucdavis.edu
Address: Physics Dept., UC Davis, 1 Shields Road, Davis, CA, USA
CoI: Sherry Suyu, UC Santa Barbara
CoI: Tommaso Treu, UC Santa Barbara
CoI: Matt Auger, University of Cambrdige
CoI: Leon Koopmans, Kapteyn Insitute
CoI: Phil Marshall, Oxford University
Title: Quantifying the line-of-sight mass distributions to time-delay lenses
Abstract:
We have recently shown that a single gravitational lens with high-quality
data can place constraints on H_0, w, and Omega_k that are comparable to
constraints from other cosmological probes. Furthermore, since each lens
makes an independent measurement of these quantities, a significant
improvement in precision can be obtained by increasing the sample size, while
also providing internal checks on systematics. This establishes lensing as a
powerful and independent tool for determining cosmography, in preparation for
the hundreds of time-delay lenses that will be discovered by future surveys.
The largest current contributor to the error budget from lensing is
uncertainty about the line-of-sight mass distribution. The proposed
observations are critical for reducing these uncertainties by providing
redshifts and stellar masses for galaxies in the light cones of the target
lens systems, and will do so with only a modest investment of observing time.
We have an approved Gemini program (GN-2012B-Q-11) that is providing these
observations on three high-quality lens systems observable in the fall
semester. This proposal requests time for the one remaining high-quality lens
system that is accessible from Gemini North.
National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360
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NOAO > Observing Info > Approved Programs > 2013A-0419 |
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